i think a meeting with the school would definitely be beneficial. i think in high school you are unlikely to be sent to the principal unless it's something really major. his year level coordinator would probably be a good place to start. explain your concerns re-discipline & let them know that you son has said that the teacher touched him & he doesn't like that. i have a feeling that your son saying get your hands off me would be taken more as a sign of attitude/aggression rather than accurately conveying that he simply does not like to be touched (i hope that makes sense!).

i do think it's good that the teacher has contacted you so you have the opportunity to meet with her/him & discuss the situation. i'm guessing if she went to the principal, they'd tell her to contact you first anyhow.

hope it works out for you